The multi-antenna technology can fully utilize space resources of signals to meet the requirement for a higher peak rate without increasing the bandwidth. The main process may be described as follows: A serial data stream at the transmitter undergoes necessary space-time processing to form multiple information sub-streams, and the information sub-streams are transmitted by multiple antennas, and recovered to the data stream at the receiver by using the detection technology. An important prerequisite for a multi-antenna system to obtain a high data transmission rate is that CSI (channel state information, channel state information) is known. In practice, however, the CSI is usually unknown. Therefore, accurate channel estimation is a key technology for ensuring transmission quality in a multi-antenna system.
At present, channel estimation is classified into blind estimation and training-sequence-based estimation. In training-sequence-based channel estimation, the transmitter inserts a certain number of reference signals into data packets, and the receiver estimates channel coefficients for the position of the known reference signals, obtains channel coefficients for the position of the data by using the channel estimation algorithm and performs data balancing and decoding. The number, position, and adopted sequence of the reference signals all affect channel estimation performance.
When the channel frequency selectivity is low and the channel is relatively flat, multiple PRBs (Physical Resource Block, physical resource block) are bundled, that is, PRB bundling (physical resource block bundling channel estimation) is used to improve the channel estimation precision.
In the prior art, when multiple PRBs are bundled for channel estimation, the position and number of reference signals remain the same as when a single PRB is used for channel estimation, causing redundancy and uneven density of the reference signals and affecting the data transmission rate.